Photochromic material containing a spiropyran compound a polyhalogenated hydrocarbon photoactivator and an acetanilide sensitizer and the use thereof in photoimaging

ABSTRACT

Spiropyran compounds suited for photographic image formation according to the present invention are spiropyrans containing at least one pyran ring having in the ortho- and meta-position to the oxygen atom a condensed benzo, naphtho or other higher aromatic polycyclic condensed ring system including these condensed rings or ring systems in substituted state e.g. an anthraceno or a phenanthreno ring system e.g. as present in a spirodibenzopyran, a spirodinaphthopyran, a spirobenzonaphthopyran, a 1,3,3-trimethylindolinobenzospiropyran, a 1,3,3-trimethylindolinonaphthospiropyran or such spiropyrans containing condensed aromatic nuclei of the anthracene or phenanthrene type. In said spiropyrans the pyran rings, the condensed benzo, the condensed higher aromatic rings as well as the 1,3,3trimethylinodolino ring may be substituted. Suitable substituents therefore are e.g. hydrocarbon groups such as alkyl groups, e.g. lower alkyl groups such as methyl, substituted alkyl groups e.g. halogen, or phenyl substituted alkyl groups, alkylene ester groups e.g. a -CH2-COOC2H5 group, alkylene carboxyl groups e.g. a -CH2-COOH group, carbonamide groups or substituted carbonamide groups e.g. a     group in which each of R3 and R4 represent an alkyl group or an aryl group e.g. a phenyl group including these groups in substituted form, and R2 represents hydrogen or an organic group e.g. an alkyl group, an aryl group e.g. phenyl group or a heterocyclic group including these groups in substituted form. Preferred sensitizing agents according to the above general formula are acetanilide and acetanilide derivatives. Examples of useful sensitizing agents according to the general formula are listed in the following Table 1.   wherein: R1 represents an organic group e.g. of the type present in a carboxylic acid chloride e.g. an alkyl group, an aryl group or heterocyclic group including these groups in substituted form, or a -NHR3 or In order to illustrate in more details the preparation of the diarylo spiro-pyran compounds and the indolino-arylospiropyran compounds the following preparation receipts are given: Preparation 1 Preparation of 3-methyldi- Beta -naphthospiropyran (compound 2 of Table 2) In a 2 litre three-necked flask, fitted with a reflux condenser and a gas inlet tube reaching nearly the bottom of the flask are introduced:   The flask is shaken until partial dissolution of the ingredients. Dry hydrogen chloride gas is introduced at a rate, which allows complete absorption and the start of ethanol reflux. Thereupon the already highly blue coloured mixture is cooled down in a mixture of ice and sodium chloride and the introduction of hydrogen chloride gas is continued until saturation. In the reaction mixture green crystals of pyrylium salt are formed and the crystallization is allowed to proceed overnight in a refrigerator. The pyrylium salt formed is separated by suction, is washed with ethanol, and thereupon suspended in 300 ml of ethanol. Whilst stirring a 10 percent by weight aqueous solution of ammonium hydroxide is added until the mixture is definitely alkaline. During this operation the mixture becomes colourless. The obtained crystalline product is separated by suction, washed with water, and dried. Finally the spiropyran compound is recrystallized from 600 ml of benzene, separated again, and dried under reduced pressure at 50*-60*C. Yield: 45 g. Melting point: 204*C. Preparation 2 Preparation of 1,3,3-trimethylindolinobenzopyrylospiran (compound 22 of Table 2) In a 100 ml flask fitted with a reflux condenser the following ingredients are introduced:   The solution is refluxed for 2 hours, whereupon the mixture is cooled and filtered. Water is added to the filtrate. The solid is then separated by suction, washed with water, and dried in vacuo. The spiran compound is recrystallized from 15 ml of hexane. Yield: 5 g. Melting point: 93*-94*C. For use according to the present invention the compound capable of producing a dye salt with a spiropyran on exposure to activating electromagnetic radiation is preferably an organic polyhalogen compound, from which a halogen-containing radical can be separated photolytically. Compounds possessing this property are within the scope of the following general formula:   wherein: each of A, B, X, and Y are halogen atoms of the group of chlorine, bromine, or iodine, or wherein one of said groups A, B, X, or Y represents an alkyl group, including a substituted alkyl group e.g. a halogen substituted alkyl group, a hydroxyalkyl group or an aralkyl group e.g. a benzyl group, an aryl group, a substituted aryl group or an aroyl group and the other groups chlorine, bromine, or iodine, or wherein at least two of said groups A, B, X, or Y represent an aromatic acyl group e.g. a benzoyl group and the other groups chlorine, bromine, or iodine. Suitable representatives falling within the scope of the general formula are organic halides such as carbon tetrabromide,   GROUP IN WHICH EACH OF R3 and R4 represent an alkyl group or an aryl group, and R2 represents hydrogen, or an organic group. This invention relates to photographic recording and reporduction of information and to materials suited therefor. The use of particular spiropyrans in the manufacture of photographic recording materials is known e.g. from the U.S. Pat. No. 2,953,454 of E. Berman - Nat. Cash Reg., issued Sept. 20, 1960. The spiropyrans described therein are characterized as being reversibly transformable into a coloured form by activating electromagnetic energy. In many applications such reversible transformation is not desirable and therefore efforts have been made to obtain a printout colour image, the colour of which does not fade by keeping it in the dark or by a further irradiation with electromagnetic radiation differing in wavelength from the radiation originally applied. In the German Patent Specification No. 1,274,655 filed Dec. 15, 1965 by Telefunken Patentverwertungs G.m.b.H. a recording material has been described by means of which stable print-out dyestuff images can be obtained by using spiropyrans in admixture with a compound that activated with electromagnetic radiation can yield photolytically formed free radicals. The starting substances for these radicals are preferably halogenated organic compounds. The recording materials described in the latter Patent Specification need rather long exposure times with the conventional ultra-violet radiation sources. It is an object of the present invention to provide a method for increasing the photosensitivity of recording materials containing a photosensitive compound that by information-wise exposure to activating electromagnetic radiation yields a dyestuff image by reaction with a spiropyran compound. It is another object of the present invention to provide a method for making visible or intensifying a latent image or barely visible image produced with said spiropyran and photosensitive compound. Said method is called hereinafter &#39;&#39;&#39;&#39;optical development&#39;&#39;&#39;&#39; for it operates with an overall exposure in the wavelength range of electromagnetic radiation absorbed by dyestuff traces formed in the imaGe-wise exposure. It is a further object of the present invention to provide photographic materials suited for use in said methods. It has now been found that the photosensitivity for forming a directly visible image or optical development sensitivity of a recording material containing in intimate admixture: 1. at least one spiropyran compound, and 2. at least one ultra-violet radiation-sensitive compound capable of producing an exposure to ultraviolet radiation with said spiropyran compound a dyestuff salt, is increased by using in working relationship with said mixture an organic compound being: an amido, acylamino or ureido compound corresponding to the following general formula:   WHEREIN: R1 represents an organic group of the type present in a carboxylic acid chloride, a -NHR3 or a   A photographic process wherein a visible image is formed in a recording material which comprises in intimate admixture: 1. AT LEAST ONE SPIROPYRAN COMPOUND, 2. AT LEAST ONE ULTRA-VIOLET RADIATION-SENSITIVE COMPOUND CAPABLE OF PRODUCING ON EXPOSURE WITH ULTRA-VIOLET RADIATION WITH THE SPIROPYRAN COMPOUND A DYE SALT, AND IN WORKING RELATIONSHIP WITH SAID MIXTURE AN ORGANIC COMPOUND, WHICH IS AN AMIDO, ACYLAMINO OR UREIDO COMPOUND CORRESPONDING TO THE FOLLOWING GENERAL FORMULA: wherein: R, R1, R&#39;&#39;1, R2, R&#39;&#39;2, R3 and R&#39;&#39;3 represents hydrogen, an aliphatic group including a substituted aliphatic group e.g. a (C1-C20) alkyl group including such an alkyl group in substituted form, more particularly a methyl, ethyl, propyl, amyl, or hexadecyl group or halogen substituted alkyl group, halogen, nitro, hydroxy, an alkoxy or aryloxy group, a phenyl group, or a substituted phenyl group, piperidyl, an alkylene ester group e.g. a -CH2-COOC2H5 group, an alkylene carboxyl group e.g. a -CH2-COOH group, a carbonamide group or a substituted carbonamide group e.g. a   group, or R1 and R&#39;&#39;1 together represent a -(CH2)n-chain wherein n 2 or 3 to link the carbon atoms in the 3 and 3&#39;&#39; positions. Suited spiropyran ompounds and their preparation are described in the published German Patent Applications 1,274,655 filed Dec. 15, 1965 by Telefunken Patentverwertungs G.m.b.H., 1,269,665, 1,286,110, 1,286,111 and 1,286,112 all filed Sept. 30, 1966 by Telefunken Patentverwertungs G.m.b.H., and by W. Dilthey, Berres, Holterkoff, Wubken, J.Pr.Ch. (2) 114, 187 (1926), by C. F. Koelsch and W. R. Workman in J.A.C.S. 74 6288 (1952) and in J.Chem.Soc. (1934), 1571 by I. M. Heilbron and G. F. Howard. Preferred spiropyran compounds are spirodinaphthopyrans and spirobenzonaphthopyrans including such compounds wherein the naphtho- and/or benzo ring(s) is (are) substituted. An illustrative list of particularly useful spiropyran compounds is given in the following Table 2.   group, halogen, nitro, hydroxy, alkoxy, aryloxy or a substituent linking the carbon atoms in 3,3&#39;&#39;-position in the spiropyran system together e.g. a (CH2)n-chain wherein n is 2 or 3. General formulae covering particularly suited spiropyrans are the following:

United States Patent Mertens et al.

[ 1 June 28, 1974 [75] Inventors: Ludovicus Lucas Mertens,

Borgerhout; Jozef Willy Van Den Houte, Berchem; Freddy Ghisleen Van Royen, Wommelgem, all of Belgium [73] Assignee: .-Agfa-Gevaert N.V., Mortsel,

Belgium- [22] Filed: Aug. 25, 1972 [21] App]. No.: 283,756

[30] Foreign Application Priority Data Aug. 27, 1971 Great Britain 40349/71 [52] US. Cl 96/48 R, 96/48 QP, 96/45.2, 96/90 PC, 96/90R [51] Int. Cl .L G036 5/24, 603C 1/52 [58] Field Of Search 96/48 R, 45.2, 90 PC, 48 QP, 96/90 R [56] References Cited UNITED STATES PATENTS 2,936,235 5/1960 Chalkley 96/90 3,272,635 9/1966 Sprague et a1. 1. 96/90 3,285,744 11/1966 Sprague et a1. 96/90 3,486,899 12/1969 Brownm; 96/90 PC 3,547,646 12/1970 Hori et a1 96/90 3,558,3 17 1/1971 Petro ct a1. 96/90 3,642,479 2/1972 Van Allan et a]. 96/90 PC 3,660,086 Tamai et a1 96/90 PC FORElGN PATENTS OR APPLlCATlONS 1,274,655 8/1968 Germany .1 96/90 PC Primary ExaminerRonald H. Smith Assistant Examiner-Won H. Louie, Jr. Attorney, Agent, or Firm-Wil1iam J Daniel [57] ABSTRACT A photographic process wherein a visible image is formed in a recording material which comprises in intimate admixture:

1. at least one spiropyran compound,

2. at least one ultra-violet radiation-sensitive compound capable of producing on exposure with ultra-violet radiation with the spiropyran compound a dye salt, and in working relationship with said mixture an organic compound, which is an amido, acylamino or ureido compound corresponding to the following general formula:

wherein: 5

R represents an organic group of the type present in a carboxylic acid chloride, at 1 1HR or a 20 Claims, No Drawings PHOTOCHROMIC MATERIAL CONTAINING A SPIROPYRAN COMPOUND, A POLYI-IALOGENATED HYDROCARBON PHOTOACTIVATOR AND AN ACETANILIDE SENSITIZER AND THE USE THEREOF IN PHOTOIMAGING This invention relates to photographic recording and reporduction of information and to materials suited therefor.

The use of particular spiropyrans in the manufacture of photographic recording materials is known e.g. from the U.S. Pat. No. 2,953,454 of E. Berman Nat. Cash Reg, issued Sept. 20, 1960. The spiropyrans described therein are characterized as being reversibly transformable into a coloured form by activating electromagnetic energy.

In many applications such reversible transformation is not desirable and therefore efforts have been made to obtain a print-out colour image, the colour of which does not fade by keeping it in the dark or by a further irradiation with electromagnetic radiation differing in wavelength from the radiation originally applied.

In the German Patent Specification No. 1,274,655

'2 called hereinafter optical development for it operates with an overall exposure in the wavelength range of electromagnetic radiation absorbed by dyestuff traces formed in the image-wise exposure.

It is a further object of the present invention to provide photographic materials suited for use in said methods.

It has now been found that the photosensitivity for forming a directly visible image or optical development sensitivity of a recording material containing in intimate admixture:

l. at least one spiropyran compound, and 2. at least one ultra-violet radiation-sensitive compound capable of producing an exposure to ultraviolet radiation with said spiropyran compound a dyestuff salt, is increased by using in working'relationship with said mixture an organic compound being: an arnido, acylamino or ureido compound corresponding to the following general formula:

wherein:

filed Dec. 15, 1965 by Telefunken Patentverwertungs G.m.b.l-l. a recording material has been described by means of which stable print-out dyestuff images can be obtained by using spiropyrans in admixture with a compound that activated with electromagnetic radiation can yield photolytically formed free radicals.

The starting substances for these radicals are preferably halogenated organic compounds.

The recording materials described in the latter Patent Specification need rather long exposure times with the conventional ultra-violet radiation sources.

It is an object of the present invention to provide a method for increasing the photosensitivity of recording materials containing a photosensitive compound that by information-wise exposure to activating electromagnetic radiation yields a dyestuff image by reaction with a spiropyran compound.

It is another object of the present invention to provide a method for making visible or intensifying a latent image or barely visible image produced with said spiropyran and photosensitive compound. Said method is R represents an organic group e.g. of the type present in a carboxylic acid chloride e.g. an alkyl group, an aryl group or heterocyclic group including these groups in substituted form, or a NHR or the general formula are listed in the following Table 1.

TABLE 1 Number Melting of the polnt Compound Structural formula 0.) Reference for preparation Ber. 60, 219 (1927).

Arch. der Pharmazie (1926) 324.

Rec. Trev. Chim. 41, 659 (1922).

Monatsh. 48, 128.

Ber. 42, 3103 1909).

TABLE 1Continued Number Melting of the point compound Structural formula 0.) Reference for preparation 6 lTIH-C O-CH 168 .T. pr. Chem. [2] 84, 530 (1911).

7 170 Annalen 260 234 (1890).

H CC N H 8 CH; 102 Ber. 21, 1159 (1888).

H3O-C ONH'C OCHzOH CH 10 g 156 Ber. 16, 2003 (1883).

Hie-c OHN CHO 11; se Helv. Chim. Acta 11, 779.

NH-C OCHzC 0-011;

12 111 J. pr. Chem. [2184, 649 (1911);

--NHC O-GHz-SH Ber. 53, 2643 (1900).

13 242 A. Vogel, Practical Organic Chemistry, Longmans, Green and /NH Co., Ltd. London, 3rd Ed. p. 646.

14 132 J. Chem. Soc.1926,8.

NH-O O CH:

CH CONHz 82 1s 80-81 Am. Soc. 24, 763.

CHQNH o o Spiropyran compounds suited for photographic group, halogen, nitro, hydroxy, alkoxy, aryloxy or a image formation according to the present invention are substituent linking the carbon atoms in 3,3-position in spiropyrans containing at least one pyran ring having in the spiropyran system together eg a (CH ),,-chain the orthoand meta-position to the oxygen atom a conwherein n is 2 or 3, densed benzo, naphtho or-other higher aromatic polycychc c9ndensed "8 3 mcludmg these General formulae covering particularly suited spirodensed rings or ring systems in substituted state e.g. an pyrans are the following; anthraceno or a phenanthreno ring system e.g. as present in a spirodibenzopyran, a spirodinaphthopyran, a

spirobenzonaphthopyran, a l ,3 ,3- R1 Ra trimethylindolinobenzospiropyran, a l ,3 ,3- I trimethylindolinonaphthospiropyran or such spiropy- 5 /4 2 2' rans containing condensed aromatic nuclei of the an- 60 o' 6' thracene or phenanthrene type. 7 8 1 1 R In said splropyrans the pyran rings, the condensed benzo, the condensed higher aromatic rings as well as the 1,3,3-trimethylinodolino ring may be substituted.

Suitable substituents therefore are e.g. hydrocarbon groups such as alkyl groups, e.g. lower alkyl groups such as methyl, substituted alkyl groups e. g. halogen, or phenyl substituted alkyl groups, alkylene ester groups e.g. a Cl-l -COOC H group, alkylene carboxyl groups e.g. a CH COOH group, carbonamide groups or substituted carbonamide groups e.g. a

X R [R y z CH3 R1 R1 R2 wherein:

R, R,, R' R R' R and R' represents hydrogen,

an aliphatic group including a substituted aliphatic group e.g. a (C -C alkyl group including such an alkyl group in substituted fonn, more particularly a methyl, ethyl, propyl, amyl, or hexadecyl group or halogen substituted alkyl group, halogen, nitro, hydroxy, an alkoxy or aryloxy group, a phenyl group, or asubstituted phenyl group, piperidyl, an alkylene ester group e.g. a CH -COOC H group, an alkylene carboxyl group e.g. a CH- --COOH group, a carbonamide group or a substituted carbonamide group e.g. a

group, or R and R, together represent a -(Cl-l chain wherein n 2 0r 3 to link the carbon atoms in the 3 and 3' positions.

Preferred spiropyran compounds are spirodinaphthopyrans and spirobenzonaphthopyrans including such compounds wherein the naphtho-- and/or benzo ring(s) is (are) substituted.

An illustrative list of particularly useful spiropyran compounds is given in the following Table 2.

TABLE 2 Melting 01m spiropyran compound 0.)

a Hie-41114311. 20s- 15 om-ooon QE Y Q 6 CHCO0C,H5 ms OIN Spiropyran compound Melting Fog;

TABLE 2 Continued M ti Spiropyran compound 61 n8 8 mo CH, CH--C Q- I 1%r\ 0 $111 TABLE 2 Continued Melting nt. Spiropymn compound b KSO Br CH:

TABLE 2 Continued Melting uint Bplropyran compound 0.)

. :23.2 nt n e spiropyran compound Melting (point C.)

pound 2 of Table 2) In a 2 litre three-necked flask, fitted with a reflux condenser and a gas inlet tube reaching nearly the bottom of the flask are. introduced:

ethanol 1 litre butanone 22 ml (0.25 mole) Z-hydroxy-l-naphthaldehyde 86 g (0.5 mole) The flask is shaken until partial dissolution of the in- .gredients. Dry hydrogen chloride gas is introduced at a rate, which allows complete absorption and the start of ethanol reflux. Thereupon the already highly blue coloured mixture is cooled down in a mixture of ice and sodium chloride and the introduction of hydrogen chloride gas is continued until saturation. In the reactionrnixture green crystals of pyrylium salt are formed and the crystallization is allowed to proceed overnight in a refrigerator.

The pyrylium salt formed is separated by suction, is washed with ethanol, and thereupon suspended in 300 ml of ethanol.

Whilst stirring a percent by weight aqueous solution of ammonium hydroxide is added until the mixture is definitely alkaline. During this operation the mixture becomes colourless.

The obtained crystalline product is separated by suction, washed with water, and dried.

Finally the spiropyran compound is recrystallized from 600 ml of benzene, separated again, and dried under reduced pressure at 5060C. Yield: 45 g. Melting point: 204C.

Preparation 2 Preparation of l,3,3-trimethylindolinobenzopyrylospiran (compound 22 of Table 2) In a 100 ml flask fitted with a reflux condenser the following ingredients are introduced:

salicylaldehyde 3.7 g (0.03 mole) 1,3 ,3-trimethyl-2-methylene indolamine 5.l g (0.03 mole) ethanol. 90 ml The solution is refluxed for 2 hours, whereupon the mixture is cooled and filtered.

waterl saddsdltq.tltafil rate. he ..9. K ith n Parated by suction, washed with water, and dried in vacuo.

The spiran compound is recrystallized from 15 ml of hexane.

Yield: 5 g. Melting point: 9394C.

For use according to'the present invention the compound capable of producing a dye salt with a spiropyran on exposure to activating electromagnetic radiation is preferably an organic polyhalogen compound, from which a halogen-containing radical can be separated photolytically. Compounds possessing this property are within the scope of the following generalforrnula:

wherein:

each of A, B, X, and Y are halogen atoms of thegroup of chlorine, bromine, or iodine, or wherein one of said groups A, B, X, or Y represents an alkyl group, including a substituted alkyl group The amount of the sensitizing agent according to the above general formula may vary within a wide range depending on the intensity of the desired effect.

Preferred amounts of sensitizing agent are in the weight ratio range of 1:1 to 0.121 with respect to the spiropyran compound(s).

The spiropyran compound(s) are used preferably in admixture with a 5- to 20-fold amount by weight of photosensitive organic halogen compound such as carbon tetrabromide. This ratio, however, is not limitative since useful results can be obtained with e.g. the spiropyran and photosensitive polyhalogen compound in a xati bxa jshtip th raqsasilal to A sensitizing agent of the above general formula may be used alone grin combination with one or more other 17 sensitiz'ingcompounds belonging to one of the following classes:

(A) organic compounds containing two groups of different electron-affinity (the term group includes group as well as atom) linked to each other through a conjugated system.

Useful sensitizing agents of class (A) are those having one of the following general formulae (1), (II), (III), W 9st,

wherein:

D represents an electron-donating group e. g. an alkyl (preferably C -C alkyl), cycloalkyl or aralkyl substituted amino or hydroxy group, preferably a monoalkyl amino group, a dialkylamino group or an alkoxy group,

Z represents a conjugated system e.g. a polymethine chain or an azamethine chain including such chain that is substituted or makes part of a ring structure e.g. a phenylene or a naphthylene ring,

R represents hydrogen, a hydrocarbon group e. g. an alkyl, an aryl or a heterocyclic group preferably a methyl group or a phenyl group, or the necessary atoms to form a homocyclic or heterocyclic ring with an atom of the group Z,

Q represents the non-metallic atoms necessary to complete a ring or ring systemin which the group C=X through a conjugated system is linked to an electron-donating group as described for D,

X represents an electronegative atom or group e.g.

oxygen, =N-R wherein R is hydrogen or an aromatic group, sulphur, selenium,

electron-attracting groups and other bivalent known in organic chemistry, preferably however X represents oxygen or sulphur,

0 represents the non-metallic atoms necessary to.

complete a ring or system wherein the group .t atta q ssrqsr as? r t ssrlsro s. 5719i:

mula (I) are:

ocarbonyl group, a sulf onyl group or a dicyano methylene group, or represents the atoms necessary to form with the carbon atom of the group Y represents anelectron-attracting group e.g.

n|| If 7S? 0 o 0 h swap, t

(J. ll X wherein X has the same meaning as described above, 7

vQ represents a heterocyclic nucleus containing an electron-donating group e.g. a dialkylamino group that is linked through a conjugated system with the g up...

wherein P and Q each represent an electronattracting substituent e. g. a cyano group or wherein P and Q together represent the atoms necessary to close a heterocyclic ring with electronegative character e.g. as present in merocyanine dye-s such as a ketomethylene ring, the rhodanine nucleus being group or a plurality of said groups linked to each other, or L L and L together represent a double bond linkingthe group to the group Preferred compounds falling within the scope of for- 19 20 Preferred compounds falling within the scope of for- Preferred compounds falling within the scope of formula (ll) are: O mula (IV) are styryl dye bases and styryl vinyl dye bases and compounds such as:

(3) Hail CH3 5 12 r I O CH: )Q. C N H3O 6 CH3 ll -N CH:

( H30 a Biz Ifay 21gitf15 7S'tates patent speclficatlon 2,793,792 of J B Prlkmgton, issued HaC W V CH3 (13 9 Q WM" 15 (5) H3O CH3 Q Q N- N 0 l \NO va which: M M-V H, H V

(6) H3O CHa /N CH=C H0 N\ 3 0, A 3 w s r ,,.r-.

v (Ref. J. Prakt. Chem. [2], 157, p. 219 (1941).

7) H3O CH3 it l :40 A A UWVMQHLvHN H ...M h

Preferred compounds falling within the scope of for- H3O I I mula (III) as described e.g. in the Belgian Patent Speci- N fication 747,849 filed March 23, 1970 by Gevaert-Agfa N.V. corresponding with the US. Pat. appl. Ser. No. "a m 0 ..7 22,376. Representatives thereof are e. g.

. "i Ref. Ber. 89, p. 1748 (1956). (8) CH3 40 0 V000,. H3O Ill N- o 15 0 I HaC Q 4 C/ \C=O' a i V I (9) 1130 E Ref. Ber. 89, p. 174s 195s).

, a a /N =0 I .0 s.

S UQAI/ \C=S CH3 HaC\ l I i H502/ M ,7

r V Q;. M

HgCz 2 5 Ref. U.S. pat. spec. 3,189,447 of Wilhelm Mengebauer, Martha Tomanek and Hans Behmenburg, issued June 15, 1965.

Preferred compounds falling within the scope of formula (VI) are described in the United Kingdom Patent Specification 853,880 filed December 16, 1957 by KalleAG, e .g.:

Preferred compounds falling within the scope of formula (V) are merocyanines e.g. those described in the United Kingdom Patent Specification 1,131,238 filed November 16, 1965 by Eastman Kodak Co. Represenet r es, hsreqf e e. .-a or (lJHa Hg Hg,

B. organic compounds containing an aromatic nucleus or aromatic ring system in which two adjacent carbon atoms are common to said nucleus or ring system and to an adjacent ring having no conjugated character and which at one end is linked to the aromatic nucleus or ring system through a car hon-carbon bond and which at the other end is linked to said nucleus or ring system through an electron-donating group such as a secondary or tertiary amino group, said organic compounds including those having a said nucleus or ring system in substituted form.

Preferred compounds belonging to class (B) are described e. g. in the Belgian Patent Specification 727,433 filed Jan. 27, 1969 by Gevaert-Agfa NV. corresponding with the US. Pat. appl. Ser No. 793,881. Repressntati s tt zs p ar a r CH3 GH5 an 1% I" CH3 I H l wherein:

n is a positive integer of at least 2, and R represents hydrogen or an alkyl group including a substituted alkyl group. C. Polymeric compounds containing recurring units corresponding to the following general structure:

R1 R2 Laafil wherein:'

Z represents a sulphur atom or a single bond,

A represents a single bond or a bivalent hydrocarbon group e.g. a CH group,

R represents hydrogen or a lower alkyl group, e.g. a

methyl group,

1 R represents hydrogen or alo'wer alkyl group, e.g. a

' each of Q3 and Q4 represent a hydrogen atom or together the atoms necessary to close an adjacent carbocyclic nucleus or ring system including such a ring or ring system in substituted form, preferably an aromatic ring (e.g. a benzene ring)including a' substituted aromatic ring e.g. a halogen substituted (chlorine, bromine, or iodine-substituted) benzene ring, and

' esents 1 or The N-vinyl polymers pared by application of one of the various known polymerization procedures, e. g., by pearlor emulsion polymerization or by polymerization in solution, whereby the initiation of the polymerization can occur by free radicals, by ion formation, or by radiation e.g., with actinic light. It is to be noted that the polymerization degree is not critical and can vary between wide limits. As far as the copolymers are concerned, it is further to be noted that the content of groups corresponding to the general formula given hereinbefore is not critical and, as shown further on in the table of copolymers containing N-vinylcarbazole units, it can vary between wide limits, say, e.g. between 20 and 95 percent, taking into account the properties of the compounds used in the preparation of the cop olymers and the required sensitizing and/or mechanical properties. In general, the best results are obtained with copolymers having a content of vinylcarbazole units between 40 and 90 The preparation of suitable poly-N-vinylcarbazoles is described e.g. in the German Patent Specifications 931,731 filed Mar. 4, 1953, 936,421 filed Feb. 20,

p 1953, 1,097,680 filed Oct. 15, 1959 all three by B.A.S.F., and 1,158,367 filed July 18, 1962 by Gevaert Photo-Producten N.V., and the US. Pat. No. 2,072,465 of W. Reppe, E. Keyssner and E. Dorrer, is-

sued March 2, 1937. The preparation of poly-N-vinyl-' pyrrole proceeds analogously. I

The preparation of suitable N-vinylcarbazole copolymers is described in the United Kingdom Patent Specification 964,875 filed April 21, 1960 by Gevaert Photo-Producten N.V. which specification also contains a preparation receipt for poly(l\l-allyl carbazole) (R CH and R H)and for po1y(N-propenyl carbazole) (R, H, R H, A Cl-l The poly-N-vinyl indoles are described in the published German Patent Application 1,906,831 filed Feb. 12, 1969 and 1,917,747 filed Apr. 5, 1969 by IBM. Corp. The polyN-vinyl diphenylamine is described in the published German Patent Application 2,007,692 filed Mar. 3, 1969 by Xerox corp. Halogen-substituted poly-N-vinyl carbazoles are described in the published Japanese Patent Applications 21 ,875/67 filed June 18, 1964, 25,230/67 filed Oct. 13,1864, 7,592/68 filed Nov. 27, 1964, 19,751/67 filed June 18, 1964 and 7,591/68 filed Nov. 18, 1964 all by Matsushita Electric Industrial Co. Ltd.

For illustrative purposes suitable vinyl copolymers' and copolymerscan be copolymer of N-vinylcarbazole and n-butyl acrylate Table 2-Cont1nued Copolymer mole of N-vinyl carbazole copolymer of N-vinylcarbazole and 2-ethyl 51.6 hexylacrylate copolymer of N-vinylcarbazole and 76.6 acryloxyethyldiethylamine copolymer of Nvinylcarbuzole and vinyl cinnamate 92.5 copolymer of N-vinylcarbazole and methyl 62.7 methacrylate copolymer of N-vinylcarbazole and isobutyl 51.8 methacrylate copolymer of N-vinylcarbazole and'lauryl 77.4 methacrylate copolymer of N-vinylcarbazole and 9.7 methylacryloxyethyl diethylamine copolymer of N-vinylcarbazole and acrylonitrile 88 graft copolymer of N-vinylcarbazole and butylaldehyde acetal of polyvinylalcohol copolymer of N-vinylcarbazole and 82.4 di(2dichloroethyl)-vinyl phosphonate copolymer of N-vinylcarbazole and styrene 49 graft copolymer of N-vinylcarbazole and polystyrene 27.3

20 copolymer of N-vinylcarbazole and vinyl napthalene 47.1

copolymer of N-vinylcarbazole and 91.5 anthracene-(9,l0)

copolymer of N-vinylcarbazole and 2-vinylpyridine 31.8 copolymer of N-vinylcarbazole and 4-vinylpyridine 32.4 copolymer of N-vinylcarbazole and 69.1 N-vinylpyrrolidinc terpolymer of N-vinylcarbazole, acrylonitrile and 20 styrene graft copolymer of a terpolymer of vinyl chloride,

vinyl acetate, and vinyl alcohol with bi -vinylcarbazole 20.1 graft copolymer ofa terpolymer of vinyl chloride, 55.1

vinyl acetate, and maleic anhydride with N-vinylcarbazole the range of :100 to 20:100.

structural parts:

Preferred organic nitrogen containing compounds are within the scope of the following'tautomeric general formulae:

wherein:

substituted form e.g.

a benzthiazole,

benzselenazole, benzoxazole, or benzimidazole ring. Particular examples of useful sensitizing agents of class (D) are:

imidazolidine-4-on-2-thiones, e. g.:

tetrahydro pyrimidine-Z-thiones, e.g.:

and thia- 26 1,3,4-dihydro thiadiazine-2-thiones, e.g.:

BIZ

thiourea compounds including substituted derivatives preferably N-phenyl thiourea compounds, e.g.:

thioamides, e.g.:

In case photoconductive zinc oxide is used as additionalsensitizing substance the recording layer preferably contains from 5 to 50 parts by weight of zinc oxide dispersed in parts by weight of binding agent containing the spiropyran compound(s) preferably in an amount of l to 50 parts by weight and the photosensitive reactant for forming the dyestuff salt e.g. a photosensitive organic halogen compound such as carbon tetrabromide and/or iodoform in an amount of 10 to 250 parts by weight. 7

As a further constituent the photosensitive recording layer according to the present invention may contain a film-forming binder. For that purpose preferably hydrophobic polymers are used that shield as much as possible the ingredients from a direct contact with the atmosphere and more especially from oxygen.

Particularly suitable binders for use in the present invention are hydrophobic polymers and copolymers e.g. containing styrene, vinyl acetate, acrylonitrile, acrylic acid ester, methacrylic acid ester, N-vinylcarbazole or butadiene units, hydrophobic cellulose derivatives, phenoxy resins or polycondensates of the polyester type e.g. polycarbonates.

These polymers may be used in admixture for improvement of the mechanical strength or adhesion of the recording layer to its support when no selfsupporting layer is produced.

In order to diminish the rate of spontaneous thermal colour formation over long periods of time as might be encountered during storage of the photographic material and processing of the photographic materials socalled antifoggants maybe added to the photosensitive composition. Suitable anti-foggants include tr'raryl compounds of group V elements e.g. triphenylstibine and sterically hindered phenols e.g. 2,6 di-tert.butyl pcresol and other reducing or atmospheric oxygen accepting agents. Triphenylstibine and analogous compounds for the purpose of the present invention are described in the United Kingdom Patent Specification No. 1,071,104 filed Aug. 14, 1964 by Horizons Inc.

Preferred amounts of anti-fogging agent such as triphenyl stibine are with respect to photosensitive carbon tetrabromide and/or iodoform within the weight ratio range of 1:100 to 2.51100.

A dry photographic coating containing the above mentioned ingredients may be formed by dissolving the binding agent(s) in a suitable inert solvent acting as dispersing or dissolving medium for the other ingredients and which is removed from the coating composition byevaporation, thus leaving a solid photographic recording layer on a properly chosen support. The supports may be of any kind used in silver halide photographic materials e.g. paper and film supports.

In order to realize the highest sensitivity, it is desirable to coat the recording layers in the absence of oxygen or to-keep them before the exposure in an oxygenfree environment.

The photosensitive organic polyhalogen compounds that in exposed state form with a spiropyran compound a dyestuff salt normally are sensitive only in a wavelength range between 400 and 250 nm.

The recording materials of the present invention containing spirodiarylopyrans and the sensitizing agents of the general formula show especially in combination with polymers and copolymers containing N- vinylcarbazole units and serving as binding agent a remarkable high white and more particularly red light sensitivity. This unexpectedly high sensitivity in the visible spectrum range is increased yet,.when during the visible light exposure the temperature of the recording layer composition israised above 40C. A very suitable operating temperature is in the range of 4070C.

' By the combination of the sensitizing agents of the general formula with organic spectral sensitizing dyes e.g. those of class (A) it is possible to further increase the spectral sensitivity in thevisible spectrum and to obtain synergetic sensitizing effects.

On using a recording material containing superposed recording layers sensitized respectively in the red, green, and blue region of the spectrum and containing the proper dye-forming combination superposed'cyan, magenta, and yellow separation images can be produced that offer a full reproduction of the multicolor original used in the information-wise exposure.

The recording materials sensitized according to the present invention are suited to product print-out images of different colour depending on the type of spiropyran compound used.

The stabilisation of the obtained prints may proceed by washing out the residual free radical generator with a suitable solvent or solvent mixture e. g. a hydrocarbon liquid such as petroleum ether optionally mixed with acetone, or by simply evaporatingit by raising the temperature when the compound involved is sufficiently volatile. For the latter purpose and the high photosensitivity, carbon tetrabromide or a mixture of carbon tetrabromide and iodoform is preferred.

According to a preferred recording and reproduction process of the present invention the information-wise exposure is carried out in such a way that first a latent image is produced, which is transformed into a visible dye image by means of a so-called optical development.

The optical development proceeds by exposing the recording layer containing the latent or barely visible image over its entire surface to visible radiation, which lies in the spectral absorption band of the products formed by the image-wise exposure and image-wise interaction of the photoexposed ingredients (1) and (2) of the above-mentioned photosensitive composition. In the overall exposure no exposure light is used, to which the photosensitive polyhalogen compound is inherently sensitive since thereby the effect of the image-wise exposure would be masked by an overall colouration. It is advantageous to use in the optical development exposure a filter absorbing all thelight corresponding with the wavelength range that is inherently absorbed by the ingredients of the non-previously exposed recording layer.

The optical development effect is speeded up markedly and the image density is increased by applying heat e. g. supplied by contact with a hot body or through infrared radiation during the overall exposure to visible light.

The optical development speed obtains a particularly high value by the use of poly-N-vinylcarbazole or the copolymers containing N-vinyl carbazole units in combination with the present amido, acylamino, or ureido compounds. The addition of a triarylstibine such as triphenylstibine to this combination intensifies the image densityobtained by the optical development procedure.

It is assumed that during the exposure applied in the optical development at least a part of the overall applied light energy is visible light absorbed by a dyestuff salt having the pyrylium structure when a diarylo spiropyran is used, or having an indolinium salt structure, when an indoline-arylospiropyran is used. Said salt seems to act as a spectral sensitizing agent for a chemical reaction between the photosensitive polyhalogen compound or radicals formed therefrom and the spiropyran.

In a preferred composition for forming print out as well as optically developable prints a mixture of carbon tetrabromide and iodoform yielding a superadditive sensitivity-effect is used.

According to an alternative embodiment of the optical development technique the recording material is first overall exposed to electromagnetic radiation to produce non-differentially over the whole recording layer latent dyestuff centres that afterwards are optically developed information-wise by a sufficiently strong information-wise exposure in the absorption bend of the dyestuff centres. Optionally the information-wise exposure proceeds simultaneously with an overall heating e.g. effected by an overall infra-red radiation exposure.

Instead of applying an overall pre-exposure to form the dyestuff centres these dyestuffs may be added e.g. applied by imbibition (diffusion) in minor amounts to the recording layer composition to act as optical development nuclei for the dye image formation by imagewise exposure.

According to a special embodiment the spiropyrans are formed in the non-exposed recording layer composition in situ by starting from the corresponding pyrylium and indolinium salts and adapting the pH in a proper way to obtain the spiropyrans that may be considered as the dyestuff precursors of the pyrylium and indolinium salts, respectively.

The information-wise exposure applied in the present invention may be a contact exposure of the direct or reflex type and likewise an optical projection exposure as used e.g. in an optical enlarging apparatus. The information-wise exposure need not be simultaneous in all parts of the recording material. The exposure may be progressive in one continuous step as e.g. in sound track recording or in successive intermittent steps provided the required information-wise change is obtained. Thus the recording material may be scanned with an image-wise modulated radiant energy spot of high intensity e.g. a laser beam, or the material may be progressively exposed through a slit, e.g. is exposed to copying light of a tubular lamp that is given a transla tion movement along the original.

A recording material of the present invention being suited for the recording of information in the form of modulated ultraviolet radiation can be used in X-ray and electron-beam recording. X-ray beams can be absorbed in high energy absorbing substances and create by means of them so-called secundary photons e.g. of the ultraviolet radiation energy band and photoelectrons that are absorbed by the photosensitive polyhalogen compound forming through its photoradicals a dyestuff salt with the spiropyran. Substances for high energy absorption that may be incorporated in the recording element contain the elements lead, mercury, bismuth, barium and/or tungsten. Lead compounds that themselves are photosensitive are preferred e.g. lead monoxide, lead bromide and lead iodide.

Suitable light sources for use in a recording method of the present invention are ultra-violet radiation sources, xenon-gas lamps, incandescent bulbs, sunlight and flash lamps. In the overall exposure for theoptical development an infra-red lamp emitting also in the visible spectrum is used preferably.

Electron beam and laser beam recording proceed with the apparatus suited for that purpose and known to those skilled in the art.

Recording materials of the present invention are very versatile in. that by the use of a proper sensitizing agent they can be applied to continuous tone or halftone re-' production. They can offer very contrasty images so that they are very suited for the reproduction of line and screen type originals and find a successful use in a great variety of graphic art applications. Due to the very high resolving power of the recording materials (the dyestuffs are formed in molecularly divided form) the recording materials of the present invention are particularly suited formicrofrlm reproduction and high precision image rendering as e.g. in the production of optical micromask masters used in the manufacturing of microelectronic circuitry. The reflex-exposure properties of the present record ing materials make them very useful in the field of document reproduction since in a reflex-contact exposure they offer print-out images of a sufficiently intense spectral density. 1

According to a special application a recording layer as described herein is used in conjunction with a magnetic recording layer and is more particularly applied to the rear side of a flexible tape support carrying the magnetic recording layer. By the use of such a material a sound track is formed in the magnetic recording layer and a visual text image corresponding with the sound track is photographed on the recording layer of the present invention.

Such a recording material'thus allows the storing of opticaland acoustic signals and the reproduction of both informations simultaneously.

The present invention is illustrated by the following examples without, however, limiting it thereto. The precentages are by weight unless otherwise indicated.

EXAMPLE 1 A mixture of 120 mg of carbon tetrabromide, 120 mg I of iodoforrn, mg of 3-methyl-di-B-naphthospiropyran, 60 mg of acetanilide, and 8 ml of a 5 solution of polystyrene in methylene chloride was coated on a non-subbed polyethylene terephthalate support.

The coating was dried in the dark at room temperature. Print-out processing of samples A and B The samples A and B were exposed through a grey wedge with a constant of 0.15 by means of a 1000 W mercury vapour bulb placed at a distance of 5 cm.

In the following table the exposure times and the number of directly reproduced wedge print steps is mentioned. 1

, Table Exposure time Amount of reproduced steps sec. Sample A Sample B By carrying out the contact-exposure in a 3M PHO- TOCOPIER 179 (copying apparatus marketed by Minnesota Mining and Manufacturing Co., St. Paul, Minn, U.S.A.) operating at full intensity for an exposure time of 30 sec 0 steps were reproduced with sample A and 2 steps with sample B. The temperature of the recording materials during their exposure was about 50C.

The image obtained was stabilized by heating the recording material for l min.;at 140C.

EXAMPLE 2 A mixture of mg of carbon tetrabromide, 120 mg if iodoform, 100 mg of 3-methyl-di-B-naphthospiropyran, 20 mg of triphenylstibine, 60 mg of acetanilide, and 8 ml of a 5 percent poly-N-vinylcarbazole solution in methylene chloride was coated at a thickness of 0.1 mm on a non-subbed polyethylene terephthalate support.

The coating was dried in the dark at room tempera ture.

Print-out processing of samples A and B The samples A and B were exposed in contact through a grey wedge with constant 0.15 in a 3M PHO- TOCOPIER 17 9 (trade name). The exposure lasted 30 sec and the temperature of the recording materials during their exposure was about 50C.

On the sample A a wedge print with 4 visible steps and on sample B a wedge print with 12 visible steps was reproduced. V I V 7 The same recording materials were used for the production of print-out images by means of a diazo copying apparatus marketed under the name ACT INA SH by La Cellophane, Paris, France, and operating with the ultraviolet radiation source of 1000 W.

In the following table the exposure times and the number of directly reproduced wedge print steps is mentioned.

The stabilization of the images was carried out by heating the recording material for l min. at 180C.

EXAMPLE 3 Preparation of the recording materials for comparative testing.

120 mg of carbon tetrabromide, 120 mg of iodoform, 100 mg of 3-methyl-di-B-naphthospiropyran, 30 mg of triphenylstibine, and 60 mg of a sensitizing agent indicated by number in the description in Table 1 are dissolved in 8 ml of a percent solution of poly-N- vinylcarbazole in methylene chloride.

The solutions are coated at a thickness of 0.1 mm. The recording layers were dried at room temperature in the dark and exposed for 30 sec. in contact with a grey wedge (constant 015) in a 3M PHOTOCOPIER 179 (trade name). The temperature of the exposed recording material was about 50C.

In the following table the number of wedge print steps obtained on the. different materials is listed.

The stabilization of the images was carried out by heating the recording materials for l min. at 180C.

EXAMPLE 4 A mixture of 120 mg of carbon tetrabromide, 120 mg f do mi 9 m q -ms -d -flnap p qpyran, 30 mg of triphenylstibine, 60 mg of pisopropylacetanilide and 8 ml of a 5 percent solution of poly-N-vinylcarbazole in methylene chloride were coated at a thickness of 0.1 mm on a non-subbed poly- EXAMPLE 5 A mixture of 120 mg of carbon tetrabromide, 120 mg of iodoform, mg of 3-methyl-di-B-naphthospiropyran, 60 mg of acetanilide, 20 mg of triphenylstibine was dissolved in 8 ml of 5 percent poly-N-vinylcarbazole solution in methylene chloride.

The solution was coated at a thickness of 0.1 mm on a non-subbed polyethylene terephthalate support. The coated layer was dried in the dark at room temperature.

Print-out processing The recording material was exposed in a a 3M PHO- TOCOPIER 179 (trade name) through a step wedge of constant 0.15. The exposure lasted 30 sec and yielded a print-out image containing 11 visible steps.

Optical development processing The recording material was exposed in the way de scribed for the print-out processing but through a transparent line original and with an exposure time of only 2 sec, whereby no directly visible image was obtained.

The image-wise exposed recording layer was then overall exposed with a 250 W-infra-red lamp placed at a distance of 20 cm and irradiating the recording layer for 25 sec through a narrow band filter mainly transmitting light in the wavelength range of 600-610 nm.

The density of the cyan image obtained was above 1.

EXAMPLE 6 A mixture of 300 mg of carbon tetrabromide, 100 mg of iodoform, 100 mg of 3-methyl-di-B-naphthospiropyran, 30 mg of triphenylstibine, 60 mg of phenacetine, 5 mg of thio Michlers ketone, and 8 ml of a 5 poly- N-vinylcarbazole solution in methylene chloride was coated at a thickness of 0.1 mm on a non-subbed polyethylene terephthalate support. The resulting layer was dried in the dark at room temperature.

The dry recording layer was exposed for 3 sec through a transparent line original in a 3M PHOTO- COPIER 179 (trade name). A print-out image of neutral colour tone with a density above I was obtained.

EXAMPLE 7 A mixture of mg of carbon tetrabromide, 120 mg of iodoform, 100 mg of 3-methyl-di-B-naphthospiropyran, 60 mg of acetanilide, 30 mg of triphenylstibine, and 8 ml of a 5 percent solution of poly-N- vinylcarbazole was coated at a thickness of 0.1 mm on a polyethylene terephthalate support. The layer was dried at room temperature in the dark.

The recording material obtained was divided up into 6 strips, which were exposed with a 100 W incandescent lamp placed at a distance of cm. During the exposure the strips were kept at different temperatures in order to have an idea about the influence of heat during the exposure. In the following table the temperatures and corresponding exposure times for reaching a density (D) =-l are mentioned.

Table Temperature C Exposure time (sec) for reaching We claim:

1. A photographic process for forming a visible image in a recording material which comprises in intimate admixture:

l. at least one spiropyran compound of the group consisting of a spirodibenzopyran, a spirodinaphthopyran, a spirobenzonaphthopyran, a 1,3,3- trimethylindolinobenzospiropyran, a 1 ,3,3- triinethylindoline-naphthospiropyran, or a spiropyran that contains a condensed aromatic nucleus of anthracene or phenanthrene,

2. at least one ultra-violet radiation-sensitive compound capable of producing on exposure with ultra-violet radiation withthe spiropyran compound a dye salt and having the general formula 34 wherein:

R is an alkyl group, an aryl group, or a NHR or group in which each of R and R is an alkyl group or an aryl group, and R represents hydrogen, or an alkyl or aryl group,

said process comprising the steps of imagewise exposing said recording material to activating electromagnetic radiation of an intensity sufficient to produce a visible image directly or a latent image that can be rendered visible by optical development. v 2. The process of claim 1 wherein said exposure pro duces a latent imageand said latent image is optically developed and comprising the steps of: imagewise exposing the recording material to activating electromagnetic radiation of an intensity sufficient to bring about a latent or barely visible image having an increased spectral sensitivity in a wavelength range outside the inherent sensitivity range of the ultra-violet light sensitive compound, and then uniformly exposing the entire imagewise exposed recording material to light within the wavelength range for which the initially exposed portions are of increased sensitivity relative to the initially non-exposed portions, thereby increasing the visibility of said initially formed image.

3. The process of claim 1 wherein said exposure produces a latent image and said latent image is optically developed and comprising the steps of: uniformly exposing the entire recording material to electromagnetic radiation of an intensity sufficient to bring about in the recording material an increase in its spectral sensitivity in a wavelength range outside the inherent sensitivity range of the ultra-violet light-sensitive compound, and then imagewise exposing the overall exposed recording material within the wavelength range for which the overall exposed recording material is of increased sensitivity to increase the visibility of the initially formed ganic compound, which is an amido, acylamino or ureido compound corresponding to the following general formula:

image.

4. A photographic process according to claim 1 wherein said spiropyran compound corresponds to one of the following general formulae:

wherein:

R, R R R R R and R' each represent hydrogen, alkyl, alkyl substituted with halogen, alkyl substituted with an ester group, alkyl substituted with 30 a carboxyl group, alkyl substituted with a N- phenylcarbamyl group, a hydroxy group, an alkoxy group, an aryloxy group, a phenyl group, piperidyl, acetyl, halogen, nitro, or R and R, together represent a (CH ),,chain wherein n 2 or 3 to link 35 the carbon atoms in the 3 and 3 positions together.

5. A process according to claim 1 wherein said mixture is used in combination with at least one sensitizing compound of the following classes. 40

A. an organic compound containing two radicals of different electron-affinity linked to each other through a conjugated system, and having one of the following general formulae (1), (II), (III), (IV), (V)

' a 65 wherein:

D represents an elctron-donating group selected from an amino group substituted with alkyl, cy-

cloalkyl or aralkyl, a hydroxy group or a hydroxy group substituted with alkyl, cycloalkyl or aralkyl,

Z represents a polymethine chain, an azamethine chain, phenylene or naphthaline,

R represents hydrogen, an alkyl group, an aryl group or the necessary atoms to form a homocyclic or heterocyclic ring with an atom of the group 2,

Q represents the non-metal atoms necessary to complete a ring or ring system in which the group C=X is linked through a conjugated system of methine groups or of a chain of methine groups bound to nitrogen to a group D,

X represents an electronegative atom or group being selected from the group consisting of oxygen, =NR wherein R is hydrogen or an arch matte rasp. s h Selenium, or

Q represents the necessary atoms to form with the V 7 carbon atom of the group a heterocyclic ring having an electronegative character with respect to the group D,

Y represents an electron-attracting group selected from the group consisting of V n in X has the above meaning, M

Q, represents a heterocyclic nucleus, containing an alkylamino group, P and Q each represent an electron-attacting cyano group, or P and Q together represent the necessary atoms to close a heterocyclic ring with electronegative character, each of L L represent a methine group, and L represents a monovalent chemical bond, a

V I wher group or a plurality of such groups linked to each other, or L L and L represent together a double bond linking the group to the group B. organic compounds containing an aromatic ring having two adjacent carbon atoms thereof in common with an adjacent ring free of conjugation, said adjacent ring at one end being linked to said aromatic ring through a carbon-carbon bond and at the other end is linked to said ring through an electron-donating group and having one of the following structural formulae:

8. A process according to claim 1, wherein said ultra- A violet radiation-sensitive compound is carbon tetrabromide, iodoform, or a mixture thereof. 1 9. A process according to claim 1, wherein the recording material contains as anti-fogging agent at least I" CH8 I 10 one of a triaryl compound of a group V element or a J:--o sterically hindered phenol.

CH3 0.43m 10, A process according to claim 1, wherein the mix- \N CH3 ture includes at least one binding agent, selected from 1 the group of polymers and copolymers comprising sty R g V, rene, vinyl acetate, acrylonitrile, acrylic acid ester, methacrylic acid ester, N-vinylcarbazole or butadiene Whefemi units, a hydrophobic cellulose derivative, aphenoxy 11 is a Positlve Integer of at least 2, and resin or a polycondensate of the polyester type includ- I R is y g or an yl PQ ing a polycarbonate resin. (C) Polymenc fompounds 9" recurring umts 2O 11. A photosensitive recording material for the direct ,Of h followmg general s e a production of a visible image by imagewise exposure to activating electromagnetic radiation which comprises a l 1 layer of an intimate mixture consisting essentially of:

cH- I 1. 1. at least one sprropyran compound ofthegroup A conslstlng of a spirodibenzopyran, a spirodinaphl; thopyran, a spirobenzonaphthopyran, a 1,3,3- Qa- Q1 trimethylindolinobenzospiropyran, a 1 ,3 ,3- I trimethylindolino-naphthospiropyran, or a spiropy- Q2 ran that contains a condensed aromatic nucleus of Z anthracene or phenanthrene, 2. at least one ultra-violet radiation-sensitive comwherein. i

Z represents a sulphur atom or a single bond, F- capable pr9ducmg exposure with A represents a single bond or a divalent hydrocap tra-vlolet radiation with the spiropyran compound be group, a dye salt and having the general formula R, represents hydrogen or a lower alkyl group, A X R represents hydrogen or a lower alkyl group, Q and'Q each represent a hydrogen atom or together the necessary atoms to close an adjacent B Y carbocychc nucleus 40 wherein: each of A, B, X and Y is a chlorine, bromine, Q and Q4 each represent a hydrog atom or iodine atom, or each of said groups A, B, X or Y is gether the necessary atoms to close an ad acent an alkyl group, an aryl group or an amy] group and the carbocychc nucleus, and other groups are each chlorine, bromine, or iodine, or n represents or 2; two of said groups A, B, X or Y each is an aromatic acyl D. a tautomenc organic nitrogen containing com group and the other groups chlorine, bromine, or iopound corresponding to the following general fordine, mula: and in working relationship with said mixture an organic compound, which is an amido, acylamino or ureido compound corresponding to the following gen- Z 2 Z eral formula: xfinllk Hi-111E Rr-CNHR; in which: X represents oxygen, sulphur, selenium or the i rou g p wherein: I R, is an alkyl group, an aryl group, or a NHR or --NR a V V mm 3 in which R is hydrogen, or an alkyl, allyl, or phenyl group, and Z represents the necessary atoms to close a 5- or- 6-membered heterocyclic nitrogen-containing group in which each of R and R is an alkyl group ring system, and or an aryl group, and E. an inorganic photoconductive metal compound in R represents hydrogen, or an alkyl or aryl group.

which said metal is zinc or lead. 6, A photographic process according to claim 1, wherein the re r i materi a t t e f matisin 9f.

1 12. A photosensitive recording material according to claim 11, wherein said spiropyran compound corresponds to one of the following general formulae; 

1. AT LEAST ONE SPIROPYRAN COMPOUND,
 2. AT LEAST ONE ULTRA-VIOLET RADIATION-SENSITIVE COMPOUND CAPABLE OF PRODUCING ON EXPOSURE WITH ULTRA-VIOLET RADIATION WITH THE SPIROPYRAN COMPOUND A DYE SALT, AND IN WORKING RELATIONSHIP WITH SAID MIXTURE AN ORGANIC COMPOUND, WHICH IS AN AMIDO, ACYLAMINO OR UREIDO COMPOUND CORRESPONDING TO THE FOLLOWIJG GENERAL FORMULA:
 2. at least one ultra-violet radiation-sensitive compound capable of producing on exposure with ultra-violet radiation with the spiropyran compound a dye salt and having the general formula
 2. The process of claim 1 wherein said exposure produces a latent image and said latent image is optically developed and comprising the steps of: imagewise exposing the recording material to activating electromagnetic radiation of an intensity sufficient to bring about a latent or barely visible image having an increased spectral sensitivity in a wavelength range outside the inherent sensitivity range of the ultra-violet light-sensitive compound, and then uniformly exposing the entire imagewise exposed recording material to light within the wavelength range for which the initially exposed portions are of increased sensitivity relative to the initially non-exposed portions, thereby increasing the visibility of said initially formed image.
 2. at least one ultra-violet radiation-sensitive compound capable of producing on exposure with ultra-violet radiation with the spiropyran compound a dye salt and having the general formula
 3. The process of claim 1 wherein said exposure produces a latent image and said latent image is optically developed and comprising the steps of: uniformly exposing the entire recording material to electromagnetic radiation of an intensity sufficient to bring about in the reCording material an increase in its spectral sensitivity in a wavelength range outside the inherent sensitivity range of the ultra-violet light-sensitive compound, and then imagewise exposing the overall exposed recording material within the wavelength range for which the overall exposed recording material is of increased sensitivity to increase the visibility of the initially formed image.
 4. A photographic process according to claim 1 wherein said spiropyran compound corresponds to one of the following general formulae:
 5. A process according to claim 1 wherein said mixture is used in combination with at least one sensitizing compound of the following classes. A. an organic compound containing two radicals of different electron-affinity linked to each other through a conjugated system, and having one of the following general formulae (I), (II), (III), (IV), (V) or (VI):
 6. A photographic process according to claim 1, wherein the recording material after the formation of a visible image is uniformly heated to bring about image stabilisation.
 7. A process according to claim 1, wherein R1 is methyl in said organic compound.
 8. A process according to claim 1, wherein said ultraviolet radiation-sensitive compound is carbon tetrabromide, iodoform, or a mixture thereof.
 9. A process according to claim 1, wherein the recording material contains as anti-fogging agent at least one of a triaryl compound of a group V element or a sterically hindered phenol.
 10. A process according to claim 1, wherein the mixture includes at least one binding agent, selected from the group of polymers and copolymers comprising styrene, vinyl acetate, acrylonitrile, acrylic acid ester, methacrylic acid ester, N-vinylcarbazole or butadiene units, a hydrophobic cellulose derivative, a phenoxy resin or a polycondensate of the polyester type including a polycarbonate resin.
 11. A photosensitive recording material for the direct production of a visible image by imagewise exposure to activating electromagnetic radiation which comprises a layer of an intimate mixture consisting essentially of:
 12. A photosensitive recording material according to claim 11, wherein said spiropyran compound corresponds to one of the following general formulae:
 13. A photosensitive recording material according to claim 11 wherein the recording material in addition to said mixture contains at least one compound belonging to one of the following classes: A. an organic compound containing two radicals of different electron-affinity linked to each other through a conjugated system, and having one of the following general formulae (I), (II), (III), (IV), (V) or (VI):
 14. A photosensitive recording material according to claim 13, wherein said material contains said mixture in layer form and includes poly-N-vinylcarbazole or a copolymer containing N-vinyl carbazole units as the sole binding agent therefor.
 15. A photosensitive recording material according to claim 11, containing as an antifogging agent at least one of a triaryl compound of a group V element or a sterically hindered phenol.
 16. A photosensitive recording material according to claim 11, wherein the recording material contains the spriopyran compound in admixture with a 1 to 50-fold amount by weight of the photosensitive organic polyhalogen compound.
 17. A photosensitive recording material according to claim 14, wherein the recording material contains such spiropyran compound and poly-N-vinylcarbazole in a ratio by weight within the range of 80:100 to 10:
 100. 18. A photosensitive recording material according to claim 17, wherein the organic polyhalogen compound is photosensitive carbon tetrabromide, iodoform, or a mixture thereofpresent with respect thereof present said poly-N-vinylcarbazole in a ratio by weight in the range of 160:100 to 20:100.
 19. A photosensitive recording material according to claim 11 wherein R1 is methyl in said organic compound.
 20. A photosensitive recording material according to claim 11, wherein said ultraviolet radiation-sensitive compound is carbon tetrabromide, iodoform, or a mixture thereof. 